In other words, Scarborough can't believe Krugman says we can wait until Medicare spending is a problem before doing more about it. Of course, the arithmophobic Scarborough can't explain why Krugman is wrong — aside from saying everybody he talks to thinks so too — which is why Scarborough outsourced the job to the senior economist at the RAND corporation. But, unfortunately for Scarborough, he seems to have found an economist who doesn't know much about the subject — at least judging from the freshman-level errors throughout. Here are the lowlights from this piece, ostensibly arguing that long-term debt is our gravest short-term economic problem. (Note: Excerpts are italicized).

1) From the beginning of 2002, when U.S. government debt was at its most recent minimum as a share of GDP, to the end of 2012, the dollar lost 25 percent of its value, in price-adjusted terms, against a basket of the currencies of major trading partners. This may have been because investors fear that the only way out of the current debt problems will be future inflation.

It wasn't. Inflation was low, and investors didn't expect that to change, over the last decade. Core PCE inflation averaged 1.9 percent over this period, while 10-year breakevens, which tell us market expectations of future inflation (going back to 2003), averaged 2.18 percent. Now, the financial crisis depressed both inflation and inflation expectations, but, as you can see in the chart below, the latter mostly leveled off around a healthy 2.5 percent for most of the last 10 years. If markets feared future inflation in the face of mounting debt, they sure had a funny way of showing it.

The Atlantic

This persistently low inflation, and expectations thereof, meant the Fed could, and did, keep interest rates low — and lower rates tend to cause a lower dollar. In other words, this wasn't a story about debt. Indeed, as you can see in the chart below, the big decline in the dollar happened between 2002 and 2007, when debt levels were relatively low, while the dollar is actually higher today than it was in 2008, despite the big debt run-up.

The Atlantic

2) More troubling for the future is that private domestic investment—the fuel for future economic growth—shows a strong negative correlation with government debt levels over several business cycles dating back to the late 1950s. Continuing high debt does not bode well in this regard.

This is a correlation masquerading as a legitimate point. Recessions happen when private investment falls, and recessions increase deficits and debt due to lower revenues and higher safety net spending. In other words, deficits and debt rise because investment has fallen, not vice versa. Now, it's true that too-big deficits can crowd out private investment during a boom — that's the legitimate point — but we know that's not a problem now since interest rates are still so low.

3) But the economics profession is beginning to understand that high levels of public debt can slow economic growth, especially when gross general government debt rises above 85 or 90 percent of GDP.

As Mike Konczal of the Roosevelt Institute points out, the idea that growth slows down when debt hits 90 percent of GDP has not been proven. It's just a correlation. And, again, it probably gets the causation backwards — low growth causes high deficits and debt, not vice versa.

4) The U.S. share of global economic output has been falling since 1999—by nearly 5 percentage points as of 2011. As America's GDP share declined, so did its share of world trade, which may reduce U.S. influence in setting the rules for international trade.

It's not clear what cutting Medicare would do about China's rapid rise. Poorer countries tend to grow faster than richer ones — that is, they converge — and that won't change regardless of whether we raise the eligibility age for Medicare or not. And besides, a richer China (and India, and Brazil, and ...) is good for us, if not our power, since it means more markets for our goods. It's odd that the same people who argue against progressive taxation because growth isn't zero-sum take a decidedly different view when it comes to international growth.

***

This entire debate is a bit surreal. Nobody disputes that healthcare spending, including Medicare, is on an unsustainable trajectory. It's a matter of what to do to "bend the curve" and when to do it. Scarborough wants to increase the eligibility age, and he doesn't think it can wait, because ... well, it's not clear why. He's not saying anything bond investors don't already know, and yet the inflation-adjusted yield on the 30-year bond is only 0.61 percent. If Scarborough is right and bond investors are wrong, then there's a tremendous money-making opportunity in shorting long-term bonds. I wonder if he has the courage of this particular conviction.

But there's another reason, quiescent bond vigilantes aside, for waiting to deal with our long-term debt. We need more time to figure out how to do it. If we knew how to slow healthcare inflation, we would have slowed healthcare inflation. But we don't. Now, Obamacare introduced payment reforms and "death panels" (IPAB — the Independent Payment Advisory Board) to try to restrain spending, but we don't know if or how much they'll work, though there are some hopeful signs. The CBO just reported that healthcare spending has slowed so much the past few years that it's revised down projected federal healthcare spending by $200 billion over the rest of the decade — or $50 billion more than raising the eligibility age from 65 to 67 would save. In other words, the things we know how to do won't save that much, and the things we don't know how to do might save much more. That's why we should play for more time.

Our elites are good at manufacturing crises, if nothing else, but Scarborough can't manufacture a debt crisis today. Markets won't cooperate — and with good reason. They're more concerned about growth than debt, because they've done the math and realize the former is the only solution to the latter.